Bloomberg News (March 25, 2009) reported a speech by San Francisco Fed president Janet Yellen in which she called for authority for the central bank to issue its own debt. The request must have most people perplexed, especially since her rationale was delivered in Fed-speak. “Issuing such debt would reduce the volume of reserves in the financial system and push up the funds rate without shrinking the total size of our balance sheet,” Yellen said.

Actually, Yellen, who is also an economist, is addressing a very serious issue. It is one that critics of current Fed policy have been raising for some time.

The Fed is loading up its balance sheet with illiquid assets, including many dubious assets taken in as collateral for loans of money and Treasury securities to financial institutions. In the process, the Fed has an ever diminishing supply of highly liquid (and safe) Treasury securities on its own balance sheet.

Critics like economic historian Anna J. Schwartz and former Fed attorney Walker F. Todd have pointed out that the Fed will have a technical problem if it wants to start sopping up all the liquidity it has created. In a 2008 paper in International Finance, Schwartz and Todd wrote that “it is fair to ask what the Fed intends to do if it decided that it would tighten monetary policy by raising interest rates.” Without a sufficient supply of highly liquid assets to sell in the markets, the Fed would need to dispose of its illiquid assets at losses. That would possibly drive up interest rates more than desired.

Yellen’s call for the power to issue Fed debt signals a number of things. First, the Fed, contrary to recent happy talk from other officials, is worried about inflation. Second, its critics are correct that the Fed has painted itself into a corner by taking illiquid assets onto its balance sheet. Third, the Fed wants to hold those dubious assets to maturity (hence Yellen’s point about not “shrinking the total size of our balance sheet”).

Yellen’s trial balloon drew a “no comment” from the Fed’s Washington headquarters. The issue will not go away.